Add To List

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so safety and repeat-call behavior are covered structurally. The description adds useful domain context that adding to a smart list is not supported, but says nothing about duplicate handling, whether an unknown list name creates a list, or what side effects occur.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single short sentence with the scope constraint front-loaded and no filler. Nothing in it could be removed without losing meaning.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need no explanation, and annotations carry the mutation and idempotency profile. For a two-parameter membership tool the description is nearly sufficient, with only the behavior on a nonexistent list name left unstated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% with only two required parameters, and the schema already explains "List id or exact list name" and "Bookmark id from another tool." The description adds no format, lookup-order, or validation detail beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb and resource ("Add a bookmark to a list") and parenthetically scopes which kind of list, which is the key ambiguity for this tool. It stops short of distinguishing itself by name from close siblings such as remove_from_list or create_list, but the mutation direction is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The parenthetical "a manual list, not a smart list" acts as an implicit when-not rule, so an agent learns one important exclusion. However, there is no explicit statement of when to use this versus remove_from_list, create_list, or tag_bookmark, and no mention of prerequisites such as whether the list must already exist.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.